The Seventh International Conference on Bacterial Locomotion and Signal Transduction (BLASTVII) will be held January 19-24, 2003, in Cuernavaca, Mexico. The conference, which is expected to have 200-250 participants, will focus on the molecular mechanisms of sensing and response in prokaryotic systems. The meeting format is designed to foster extensive discussions of recent developments and ideas among researchers from the United States and abroad. Approximately 50 oral presentations and 100 posters will be included in the program, allowing virtually all laboratories working in this rapidly moving field to present their key findings. Scientific sessions will compare and contrast the sensory and locomotor systems of a variety of prokaryotes, focusing on each fundamental step in their signal transduction pathways: (a) transmembrane signaling by chemo- and photoreceptors;(b) signal transmission by intracellular phosphorelay cascades; (c) sensory control of cellular motility, gene expression, and development; and (d) the mechanics of cell motility. Bacterial sensory systems have important functions in microbial ecology and in pathogenesis, and also provide useful models for understanding analogous signaling systems that occur in many eukaryotes. The BLAST meeting has become the principal forum for investigators in this field to present their current findings and to discuss emerging concepts and generalizations concerning bacterial sensing and motility. A review of BLAST VII will be published, which will summarize key findings presented at the meeting and provide a readily accessible overview of the present state of the field.